Interpretive Summary: Chickpea rust is a serious disease that causes considerable damage to this crop each year. Plant breeders are working to develop chickpea varieties that are resistant to the rust fungus but are hindered by lack of knowledge about the identification and host range of the chickpea rust. Until now, this fungus was thought to infect only chickpea and one species of Medicago. Recently the chickpea rust fungus was discovered on a weed called hairy medic suggesting that the host range was much broader than previously known. In this research chickpea rust was determined to infect a wide range of host plants in the legume tribe Trifolieae, specifically 29 species of Medicago including alfalfa and three species of Melilotus. These hosts suggest that other crops and weeds growing near the chickpea fields may serve as a reservoir for this disease-causing fungus. DNA sequences were determined to aid in the identification of this fungus. Plant pathologists and plant breeders will use this research in disease management and for developing chickpea varieties resistant to this disease as well as for more accurate idenfication of rust fungi on these hosts.